1. Field of the Invention
This invention patent relates to an apparatus and method for preventing the backflow of undesirable gases from being drawn up through a drain line and into a room. The invention is particularly useful in applications where liquid flow into the drain is infrequent, resulting in little or no liquid left standing in the P-trap to serve as a gas barrier.
2. Description of the Related Art
Sewer gas flowing back through a drain into a room is at best a nuisance and at worst a danger. Drain traps have been devised to hold water which prevent the backflow of sewer gas. However, some drains can run dry and the water in the drain trap evaporate, which can result in the backflow of sewer gas into the room. Conventional rubber drain stoppers can prevent or minimize the backflow of sewer gases, but they do not allow water to pass down the drain. The present invention is designed to solve this problem by providing an easy to install device which prevents the backflow of sewer gas but allows water to pass down the drain.